悬浮液中TiO2微粒分散性研究

研究了TiO2微粉在水介质中的分散行为。考察了不同pH值、分散剂和分散方式对TiO2粉体在水中的分散稳定性影响。利用粒度分析仪分析了分散剂对TiO2颗粒团聚行为以及稳定性的影响。并利用稳定机理对水溶液中TiO2分散稳定性作了解释。     

两种不同羧酸单体的两性聚羧酸盐水煤浆分散剂的制备及性能对比

以烯丙基醇聚氧乙烯醚500（APEG-500）、羧酸单体 （丙烯酸和衣康酸）、二甲基二烯丙基氯化铵（DMDAAC）等为原料,合成了具有不同羧酸单体的两性聚羧酸盐水煤浆分散剂。采用FTIR、1HNMR对分散剂的结构进行表征,并结合水煤浆黏度、XPS、Zeta电位、接触角、稳定性等测试,讨论了不同羧酸单体对分散剂的分散性能的影响,探究了分散剂与煤粒表面的作用机理。结果表明：当DMDAAC用量为单体质量之和的6.0%时 ,两性聚羧酸盐分散剂对水煤浆的表观黏度降低效果优于阴离子型的聚羧酸盐分散剂;羧酸单体为衣康酸的分散剂性能更优,使陕西榆林煤最大固体质量分数达到66.5%,Zeta电位由-20.8 mV变化到-31.9 mV,吸附膜厚度和饱和吸附量分别为2.56 nm和3.23 mg/g,对煤粒的润湿性更好,浆体的稳定性显著提高,表明双羧基比单羧基更能提高分散剂性能。     

Using a Brush Copolymer as Efficient Dispersant for the Preparation of Highly Stabilized Ag Nanoparticles in Aqueous Suspensions

Silver (Ag) nanoparticle has extremely high surface energy and it is difficult to find an efficient dispersant to prevent its agglomeration in suspensions. A new brush copolymer, succinic anhydride modified epoxy-amine poly[(propylene oxide)-co-(ethylene oxide)]-grafted polymer (EPOA), which can efficiently disperse concentrated aqueous suspensions of Ag nanoparticles is revealed. The dispersion efficiency of EPOA for the dispersion of a 60 nm-Ag nanoparticles in aqueous suspension is studied by measuring its sedimentation and rheological behavior, and the results are compared with those of a commercially available dispersant, ammonium poly(acrylic acid) (PAA-NH₄). Interactions between the dispersants and the Ag nanoparticles are characterized by zeta potential and adsorption analyses. Theoretical calculations are conducted to clarify the adsorption and the dominant dispersion stabilization mechanisms of the dispersants. Compared with PAA-NH₄, EPOA obtains a higher stable suspension of Ag nanoparticles with less significant sedimentation over 1 month. The dispersion homogeneity of the suspension remains excellent even at an extremely high solid loading of 30–40 wt%. According to adsorption analysis, it is suggested that both EPOA and PAA-NH₄ adsorb via single-point attachment through the carboxyl group on the Ag surface. Based on theoretical calculations, the Ag nanoparticles are better stabilized by EPOA via an electrosteric dispersion mechanism.     

磺化腐植酸接枝聚苯乙烯与粘土的相互作用及泥浆性能

磺化腐植酸接枝聚苯乙烯(SHAGPS)在粘土上有一定的吸附作用,这种吸附作用主要产生于SHAGPS中腐植酸结构部分与粘土的结合。研究了SHAGPS对粘土Zeta电位的影响和对粘土颗粒的分散作用,发现SHAGPS具有极好的抗盐抗钙性。SHAGPS的这些性能是腐植酸和磺化聚苯乙烯两部分结构协同作用的结果。API测试结果表明,SHAGPS对盐水泥浆具有良好的降滤失作用,可望成为一种抗盐性降滤失剂。     

分散剂对复合刷镀Ni-纳米SiC沉积行为影响的研究

为了解Ni-纳米SiC体系的刷镀特性,针对Ni刷镀液、纳米SiC和分散剂组成的刷镀液体系的沉降过程进行了研究.试验表明:当分散剂浓度大于2.5%时,可以充分分散纳米SiC颗粒,在沉降过程中,不易形成大的颗粒聚集体,颗粒的最终沉积密度增大,沉降粉体体积减小;在同样条件下,随着环境温度的升高,造成连续相黏度下降及扩散速度加快,使沉降速度升高;镀液中纳米SiC含量≤3g/L时,在分散剂作用下纳米SiC分布均匀稳定,沉积速度减慢.     

聚电解质分散剂对ZnO悬浮体流变性的影响

本文研究了聚电解质分散剂PMAA－NH_4对ZnO悬浮体流变性的影响。结果表明：pH在9~10.5,分散剂用量为0.2~0.3Wt％时,ZnO悬浮体粘度最低。此条件下,可制得固相量达43vol％（81wt％）、粘度仅为237mPa·S的稳定悬浮体。     

Strategies to Optimize the Capacitive Behavior of Polypyrrole Electrodes

Polypyrrole (PPR) and composite PPR-multi-walled carbon nanotube (MCNT) electrodes for electrochemical supercapacitors were manufactured using new anionic additives for PPR polymerization. The analysis of the microstructure of PPR and PPR-MCNTs and electrochemical testing data provided information on the influence of the dopants on the mechanism of chemical polymerization and properties of nanostructured PPR and PPR-MCNT materials. The increase of the size and charge of the aromatic dopants resulted in decreasing PPR particle size, reducing agglomeration, and promoted the formation of PPR coatings on MCNTs. New additives allowed for the manufacturing of advanced electrodes with high active mass loading, excellent capacitance at high charging–discharging rates, and cyclic stability. A capacitance of 2.67 F cm^?2 at a potential variation rate of 100 mV s^?1 was achieved using composite PPR-MCNT electrodes. The electrodes were applied for the manufacturing of supercapacitor cells, which showed good electrochemical performance.     

Diglyceryl acrylate as alternative additive dedicated to colloidal shaping of oxide materials – Synthesis,characterization and application in manufacturing of ZTA composites by gelcasting

The paper reports the synthesis of a new compound named diglyceryl acrylate (DGA) and its application in manufacturing of ZTA composites by gelcasting method. The compound can be used as a monomer able to polymerize in suspensions and also as a dispersing agent for fine-crystalline powders. The paper describes the synthesis of DGA, the properties of the monomer, the resulting polymer, ceramic suspensions and sintered bodies. The distribution of zirconia grains in alumina matrix was observed on SEM. Vickers hardness and fracture toughness of ZTA composites have been measured. The research revealed that with the use of DGA it is possible to obtain highly concentrated ceramic suspension (60 vol%) of low viscosity. The positive influence of the new monomer on the properties of ceramic suspensions and sintered bodies is explained on the basis of the analysis of spatial structures of all 8 regioisomers of DGA molecule.     

乙黄药体系中分散剂对利蛇纹石可浮性的影响

系统地研究了乙黄药体系中,矿泥分散剂六偏磷酸钠、碳酸钠、CMC、DB-6024、DB-60、DB-504、DB-503在不同用量和不同酸度下对利蛇纹石浮选回收率的影响,得出DB-504、DB-503、DB-60、碳酸钠、DB-6024对利蛇纹石的活化作用依次减弱,而六偏磷酸钠有较弱的抑制作用、CMC有较强的抑制作用,并对乙黄药、六偏磷酸钠、CMC、DB-503与利蛇纹石的作用机理进行了探讨。     

水基注浆成型碳化硅坯体的研究

运用注浆成型技术制备了亚微米碳化硅陶瓷复杂部件坯体。研究了分散剂、pH值对SiC水基浆料粘度的影响,以及不同固含量的SiC水基浆料和脱气泡处理对坯体密度的影响。结果表明：选用的3种分散剂的分散效果大小顺序为：四甲基氢氧化铵（TMAH）〉聚甲基丙烯酸铵（PMAA）〉聚乙烯亚胺（PEI）,且3种分散剂的最佳加入量分别为：1．8wt％、0．8wt％、0．056wt%,最佳pH值为10。对固含量为55wt%的SiC浆料磁力搅拌抽真空脱气泡处理20min可以注浆得到密度为1.64g／cm^3的碳化硅坯体。